Videotext for the twenty first century.

Day: April 14, 2017

Competitive Programmer’s Handbook – The purpose of this book is to give the reader a thorough introduction to competitive programming. The book is especially intended for students who want to learn algorithms and possibly participate in the International Olympiad in Informatics (IOI) or in the International Collegiate Programming Contest (ICPC).

Competitive Programming Book Companion Website – This book contains a collection of relevant data structures, algorithms, and programming tips written for University students who want to be more competitive in the ACM International Collegiate Programming Contest (ICPC), high school students who are aspiring to be competitive in the International Olympiad in Informatics (IOI), coaches for these competitions, those who love problem solving using computer programs, and those who go for interviews in big IT-companies.

Storage Engine: takes care of reading data between the disk and memory in a manner that optimizes concurrency while maintaining data integrity
Query Processor: 1. takes care of devising a query plan (what algorithms/operators to implement) by Query Optimizer 2. execute the query according to that plan by Execution Engine

Understanding how SQL Server executes a query – If you are a developer writing applications that use SQL Server and you are wondering what exactly happens when you ‘run’ a query from your application, I hope this article will help you write better database code and will help you get started when you have to investigate performance problems.

BI: Beer Intelligence? · The “Select ALL” parameter option [SSRS] – You all know that report parameters can be populated through a query, right? And multi-value parameters get this magical (Select All) item as first one in the dropdown list. I used the word magical in the previous sentence because this (Select All) item is not a real one. It’s a bit like a fata morgana: you can click it but it doesn’t really get selected. It only appears that way in the dropdown. But you can’t write an expression that tests if the (Select All) item is selected because it doesn’t really exist in the array. The only thing it does is it selects all items when it gets clicked.

DECLARE @local_variable (Transact-SQL) | Microsoft Docs – Variables are declared in the body of a batch or procedure with the DECLARE statement and are assigned values by using either a SET or SELECT statement. Cursor variables can be declared with this statement and used with other cursor-related statements. After declaration, all variables are initialized as NULL, unless a value is provided as part of the declaration.

The language of choice - Propositional logic was discovered by Stoics around 300 B.C., only to be abandoned in later antiquity and rebuilt in the 19th century by George Boole’s successors. One of them, Charles Peirce, saw its significance for what we now call logic circuits, yet that discovery too was forgotten until the 1930s. In the ’50s John McCarthy invented conditional expressions, casting the logic into the form we’ll study here; then in 1986 Randal Bryant repeated one of McCarthy’s constructions with a crucial tweak that made his report “for many years the most cited paper in all of computer science, because it revolutionized the data structures used to represent Boolean functions” (Knuth).1 Let’s explore and code up some of this heritage of millennia, and bring it to bear on a suitable challenge: playing tic-tac-toe.

Then we’ll tackle a task that’s a little more practical: verifying a carry-lookahead adder circuit. Supposedly logic gets used all the time for all kinds of serious work, but for such you’ll have to consult the serious authors; what I can say myself, from working out the code to follow, is that the subject offers a fun playground plus the most primitive form of the pun between meaning and mechanism.

Acilius diving beetle male front tarsus (foot) 100x If you’ve ever wondered how a diving beetle swims through the water or manages to rest just on the surface, the answer is in part because its foot is infinitely more complicated than your own. As seen above, this microscopic image of a male Acilius sulcatus (diving […]

Jan Chipchase is the founder of Studio D Radiodurans, which is sort of a modern day A-Team, except with more field research and fewer guns. For example, Chipchase is the sort of person who, for vacation, does not sip pina coladas in Bali but heads for "Kyrgyzstan, Tajikistan's GBAO region and China's western provinces". At […]

One of the most fascinating aspects of modern Formula 1 is the use of computer simulations to predict car performances and race strategies. By the early 1990s, teams like Benetton had begun to develop simple race simulators to estimate optimal strategies. Today, teams develop highly sophisticated models based on massive amounts of telemetry data. Constructing mathematical […]

While on a recent trip to Iceland, photographer Sarah Martinet had the opportunity to shoot these amazing landscapes from a plane with open windows. You can see much more of her work (as well as more from this trip) on 500px and Facebook.